diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/ext/ext.c | 31 |
1 files changed, 18 insertions, 13 deletions
diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index 90b3df2cdbbe..27b027833f06 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -3658,6 +3658,8 @@ static void put_prev_task_scx(struct rq *rq, struct task_struct *p, (rq->scx.flags & SCX_RQ_PROXY_PENDING); bool proxy_block = rq->scx.flags & SCX_RQ_PROXY_BLOCKING; bool rescue_keep = false; + bool going_idle = !proxy_put && next && + sched_class_above(&ext_sched_class, next->sched_class); rq->scx.flags &= ~SCX_RQ_PROXY_PENDING; @@ -3763,25 +3765,28 @@ static void put_prev_task_scx(struct rq *rq, struct task_struct *p, * locally runnable and can legitimately go idle with @p still * runnable (see do_pick_task_scx()). */ - if (!proxy_put && next && - sched_class_above(&ext_sched_class, next->sched_class) && - scx_task_can_stay_on_cpu(rq, p)) { + if (going_idle && scx_task_can_stay_on_cpu(rq, p)) { WARN_ON_ONCE(!sched_core_enabled(rq) && !(sch->ops.flags & SCX_OPS_ENQ_LAST)); scx_do_enqueue_task(rq, p, SCX_ENQ_LAST, -1); - - /* - * A task put on the local DSQ runs, as anywhere else. - * Here the insert can't reschedule on its own: the pick - * has settled on @next and @p is still curr, so - * resched_curr() would flag @p and __schedule() clears - * that right after the pick. Flag @next instead. - */ - if (p->scx.dsq == &rq->scx.local_dsq) - set_tsk_need_resched(next); } else { scx_do_enqueue_task(rq, p, 0, -1); } + + /* + * @p may be on the local DSQ now. With %SCX_ENQ_LAST the + * scheduler can put the last runnable task there. The plain + * insert runs when @p cannot stay on this cpu, and rescue can + * still admit it here. + * + * The cpu must not go idle with @p queued on its local DSQ. The + * usual resched doesn't work: the pick has settled on @next and + * @p is still curr, so resched_curr() would set need_resched on + * @p, which __schedule() clears right after the pick. Set it on + * @next instead. + */ + if (going_idle && p->scx.dsq == &rq->scx.local_dsq) + set_tsk_need_resched(next); } switch_class: |